一、用作介詞，表示在...上；向，朝等含義。
The book is on the table.
書(shū)在桌子上。
The spider is walking on the ceiling.
蜘蛛在天花板上爬行。
They made their own judgment on his report.
他們憑他的報(bào)告作出自己的判斷。
二、用作副詞，表示向前（移動(dòng)），進(jìn)行著等含義。
Put your coat on.
穿上你的大衣.
Move on!
向前走！
She worked quietly all night.
她整個(gè)晚上默默地繼續(xù)工作。
三、用作形容詞，表示在進(jìn)行的，在發(fā)生的等含義。
The televisionw set was on.
電視機(jī)開(kāi)著。
The light were all full on.
燈火通明。